Anode for the electrolysis of copper solutions



Patented Jan. 1, 1929.

FREDERICK LAIST AND FREDERICK earn F. relax, or anaconna, MONTANA.

ANODE FOR THE ELEGTROLYSIS OF COPPER SOLUTIONS.

No Drawing.

This invention relates to the electrometallurgy of copper and more particularly to the electrodeposition of metallic copper from solutions of its salts containing chlorides or nitrates or both such as are produced by leaching certain oxide copper ores and some Chilean ores with sulfuric acid.

It is customary to recover copper from solutions of its salts by electrodeposition using insoluble anodes and when the solutions are substantially free of chlorides and nitrates the best anode material is lead. Substantially pure or commercial low-antimonial lead is relatively cheap and easy to cast and handle, returns a good scrap value, gives a favorable Voltage and is not excessively corroded when the copper solutions are substantially free of chlorides and nit-rates, but when the copper solutions contain substantial quantities of chloridesor nitrates or both, anodes of pure lead or commercial low-antimonial lead are rapidly corroded. An object of the I v II Per cent Sb -14. 9 20. 1

Anode Per cent As 6 .5 Per cent Pb.-. ".84. 5 79. 4

Solu-{ Gr. 01 per liter .15 .15

tion Gr. HNO; per liter .60

Pounds of anode lost by corrosion per ton of copper deposited 1. 35 48 Duration of test-days 42 48 From these tables it appears not only that the lead-'antimony-arsenic-alloy anodes are much more resistant to COI'IOSlOl'l 1n the electrodepos1t1on of copper from solutions containing chlorides and nitrates but that in general the greater the chloride and nitrate content of the solutions the greater should be the antimony and arsenic content of the anodes. Further than this a definite rule for the determination of the best proportion of lead,

antimony and arsenic in an anode for uselead-antimony-arsenic alloys as anodes in the electrodeposition of copper are only slightly Application filed July 21,

spect to cost, workability, scrap value and voltage, but Which are not objectionablycoring the desirable properties of lead with reroded by copper solutions such as those referred to containing chlorides and nitrates.

We have found that certain lead-antimonyarsenic alloys are very resist-ant to electrolytes containing chlorides and nitrates and our invention, therefore, resides in the use of such alloys as anodes inthe electrodeposition of copper from solutions thereof containing chlorides or nitrates or both.

The following tables, of data of comparative tests of anodes of substantially pure lead and anodes of alloys of lead, antimony and arsenic in different proportions in the elec trolysis of copper solutions containing different quantities of chlorides and nit-rates illustrate the superiority of the alloys as anodes in the electrolysis of such solutions:

HI VII 1v V VI 63. 6 64. 0 Substantially 2.8 6.8 ure 33.6 29.2 cad.

.00 .00 473 Anodes almost completely de- 15 15 16 stroyed in 3 days.

higher than those obtainedwith anodes of substantially pureilead and the cathodes do not containv any more antimony or arsenic than when pure lead anodes are used. The alloys are readily cast into anodes.

The alloys may be prepared in any suit able way. For example, commercially pure antimony may be melted first in an iron pot and the lead and arsenic added to the molten solutions composed-of alloys of lead, antimony and arsenic containing from 1 to 15 percent of arsenic, from 15 to 7 0 percent of antimony and from 84 to 15 percent of lead.

In testimony whereof, We affix our signatures.

' I FREDERICK LAIST.

FREDERICK F. ERICK. 

